The present invention relates to window coverings and in particular, to a coextruded vertical blind louver having transparent grooved side edges, and to coextrusion dies suitable for use in extruding a slat for use as a louver.
Vertical blinds are well known in the field of interior decorating. They are similar to fabric drapes in that they are generally used to cover a window or a sliding glass door. Like fabric drapes, they may be center opening or side opening. The center opening vertical blind opens in the middle of the blind and the two halves withdraw to the two sides of the window to leave a center opening. The side opening vertical blind withdraws from one side to the other side of the window to leave a side opening.
Vertical blinds differ from fabric drapes in that the vertical blind contains a plurality of individual vanes or louvers which are similar to the slats of a venetian blind. However, the venetian blind has slats which are horizontal whereas the vertical blind has vertically suspended slats. Moreover, the vertical blind differs from the fabric drape in that the vertical blind may be at least partially open when, in fact, it remains closed. This is accomplished by a mechanical means whereby the individual vanes or louvers of the blind, which are hanging suspended from overhead, may be turned from a fully open to a fully closed position while the entire blind remains fully extended across the window or door. In addition, the vertical blind may be adjusted so that the individual louvers or vanes are oriented in a position which is intermediate to being turned fully opened or fully closed. In this manner, the vertical blind has a maximum flexibility for keeping sunlight out of the room. For this reason, the vertical blind has gained great popularity at the expense of the conventional fabric drape.
Vertical blinds currently are available with vertical louvers which fall into four major categories. The louvers may be free hanging fabric, fabric supported on a rigid vinyl shell, aluminum or rigid vinyl. Each of these four types of louvers may display different colors and patterns according to the taste of the individual purchaser. It is estimated that rigid vinyl louvers presently account for about 35 percent of all sales of vertical blinds. These louvers are produced from a rigid vinyl containing a pigmentation system which makes the louver highly opaque in order to reduce light transmission.
One type of rigid vinyl vane or louver which is popular is a louver which has side edges which include longitudinal slots or grooves running along the full length of the louver. These slots are open to the center web of the louver and are adapted to receive a color insert. The color insert may be pushed into the slots at one end of the louver and then slid along the louver surface until the color insert covers the full length and width of the louver with a new color or pattern. This allows the drapery owner to redecorate at his convenience. The owner can paint his room a new color and then, by use of new inserts, he can change the color of his vertical blind to conform to or contrast with the new color of the room. This grooved louver thus affords the owner maximum flexibility in color coordinating the vertical blind according to his needs or his whim.
Some louvers have side edges which contain grooves on both surfaces of the louver. Such louvers can have a color insert of a first color on one side and a second color on the other side. Thus, the owner of the vertical blind can have one color exposed to the room and the second color exposed to the window, as he may desire. The owner may then adjust the vertical blind to reposition the individual louvers so that the colors are reversed without changing the color inserts.
The grooved louvers described above normally have a central section or base web of a rigid vinyl which is pigmented and opaque to minimize light transmission. The grooved or slotted edges, however, are generally rigid vinyl of a clear and transparent type. This clear and transparent vinyl is used so that the edge portion of the color insert which is held in the slot or groove remains visible to the viewer.
Such clear vinyl is subject to aging caused primarily by exposure to the ultraviolet radiation component of sunlight. Among other things, the aging causes the clear vinyl to discolor so that the edge portions of the color insert appear yellowed. Other aging effects include the fact that the vinyl degrades and becomes brittle.
It is, therefore, an object of the present invention to provide a vertical blind louver having clear transparent grooved or slotted side edges which have enhanced resistance to discoloration and degradation upon prolonged exposure to sunlight.
It is also an object of the present invention to provide a novel extrusion die for producing the improved louver with the improved transparent grooved side edges.
These and other objects of the invention, as well as the advantages thereof, will become more clear from the disclosure which follows.